What does it protect against if the entire electric grid is shut down and all electronic devices are fried?
It also does not protect against a direct hit with an asteroid.
However in real life scenarios it protects against EMF surges both natural and otherwise.
And yes you are far more likely to be struck with lightning.
But it is nice when you fire up your generator or the grid is restored that you do not have to replace your entire house worth of appliances and electronics.